A pipe assembly for a district heating network, comprising a first pipe, a second pipe and, surrounding the first pipe, a first insulating layer arranged to reduce heat transfer from the first pipe outwards in a radial direction, the first pipe being arranged for a first heat transfer medium flow and the second pipe being arranged for a second heat transfer medium flow. The pipe assembly comprises a heat transfer device arranged to transfer heat from an outer surface of the first insulating layer to the second pipe, and a second insulating layer arranged to reduce heat transfer from the heat transfer device and the second pipe outwards in the radial direction, the thermal conductivity of the heat transfer device being substantially better than the thermal conductivity of the first insulating layer and the thermal conductivity of the second insulating layer.